1. Field of the Invention
This invention relates to a X-Y movement mechanism and, more specifically, to such a movement mechanism which has a low profile which enables a movable member to be mounted directly on a fixed base in a manner which allows X-Y guide means to be generally confined therebetween.
2. Description of the Prior Art
There are in the prior art a number of devices capable of supporting a movable member for movement in an X and/or Y direction relative to a fixed base. Although these devices include features which may be attractive or desirable for various uses, the devices are typically configured to provide satisfactory results depending on the particular purpose for which and environment in which they are primarily intended.
For example, U.S. Pat. Nos. 4,189,953; 4,372,223; 4,409,860; 4,628,756; 4,972,574; and 5,115,354 disclose fixed base elements having channel or rail means for guided movement of an intermediate member and a top member thereon in a first direction. The intermediate member in turn includes some form of channel or rail means for support of the top member to facilitate separate movement of the top member in a second direction.
U.S. Pat. No. 4,729,536 includes a similar configuration of a base, intermediate and top member which employs rods rather than channel or rail guide means as employed in the devices discussed hereinabove.
Similarly, U.S. Pat. No. 5,040,431 discloses a movement guiding mechanism which primarily relies upon hydrostatic gas or air bearing mounting pads in a similar arrangement of base, intermediate and top members thereof. U.S. Pat. No. 4,978,233 discloses a different hydrostatic bearing assembly which is utilized for the control of movement in one direction only.
On the other hand, U.S. Pat. No. 4,648,723 discloses a movable stage portion disposed between two movable guides. The first guide moves in an X-direction and the second guide moves in the Y-direction for the selective positioning of the stage portion disposed therebetween in the X and/or Y directions.
U.S. Pat. No. 4,270,404 discloses a block which is disposed for movement on a flat base plate. The block is driven in the X direction and/or Y direction by a relatively complicated means including the selective rotation of a pair of side-by-side screws that drive helical gears which operatively engage helical racks on the block. In a similar manner, the device disclosed in U.S. Pat. No. 4,341,128 employs a pair of screws disposed one above the other. In alternative embodiments, the movable stage can be located between or above or below the screws for movement in the X direction and/or Y direction by the selective rotation of the screws.
U.S. Pat. No. 4,193,317 discloses a more complicated fine position control device which may use a laser beam for recording output information of a computer.
While all of the devices disclosed hereinabove may be appropriate for the particular purpose and environment in which they are intended, there remains a need for any X-Y movement mechanism, which is simple and reliable and provides an overall configuration having a relatively low profile, for the proper control of a movable member in an X direction and/or Y direction relative to a fixed base. Some of the prior art devices disclosed hereinabove include rail guide means which are not capable of withstanding severe lateral force or pressure and are exposed to and susceptible to damage from the environment. Others include relatively light rod means or sensitive bearing pads which might also be damaged by the environment and incapable of withstanding significant lateral forces. Still others include screw and gearing means which are relatively complicated and could be difficult to properly maintain.
On the other hand, there remains a need for the utilization of an X-Y movement mechanism in various heavy-duty machines such as that disclosed in a patent application entitled "Portable Vertical Boring Machine", which was filed on the same date as the present application by the same inventor and has been assigned to the same assignee. The invention disclosed therein is directed to a portable vertical boring machine which is capable of boring and/or facing a circular region of large circular components or other work pieces which have central axes which are disposed vertically during the boring and/or facing process. The particular machine disclosed therein includes means for mounting the large circular component in a fixed horizontal position with the central axis extending in a vertical direction. The machine includes tool support extending generally vertically for rotation about the central axis. The machine also includes a configuration for moving the tool support in the X and Y directions in the horizontal plane relative to the fixed component to insure alignment of the tool support, and the axis of rotation thereof, with the central axis. The configuration for moving the tool support in the X and Y direction is a specific embodiment of the invention which is the subject of the present application.
While the particular portable vertical boring machine of the co-pending application filed on the same date as the present application represents a specific application of the present invention, it should be understood that many other applications may exist in the machining art or similar arts for an X-Y movement mechanism for the control movement of a member on a fixed base which is relatively simple to provide and easy to maintain. Further, because of the forces required in such machines, it is appropriate to include an overall configuration with the movable member being directly mounted on the fixed base to provide an overall low profile for the mechanism. Additionally, because of the environment in which such heavy machinery is employed, which environment could include metal shavings or chips, it is appropriate for the overall configuration to include means for insuring that the X-Y movement mechanism will not be subjected to such metal chips, shavings, or other extraneous material which could interfere with the overall operation of the mechanism. While the portable vertical boring machine of the co-pending application represents one use of such an X-Y movement mechanism, the introduction of such a mechanism having the preferred overall features will result in its use in any number of other machines or devices to improve the operation and reliability thereof.